Not applicable.
This invention relates to the maintenance of automobile internal combustion engines and, more particularly, to a method and apparatus for cleaning an exhaust gas recirculation system on such engines.
Exhaust gas recirculation (xe2x80x9cEGRxe2x80x9d) systems were first used on motor vehicles in the early 1970""s and have become well-known in the art. Broadly viewed, EGR systems remove a portion of the exhaust gas from the exhaust manifold and reroute the gas back to the combustion chamber. This rerouted gas cools the chamber and dilutes the oxygen content in the chamber to control detonation. An EGR valve opens to release the rerouted exhaust gas into the combustion process, and controls the combustion temperature and the timing of the engine to achieve optimum efficiency.
The EGR process initiates as exhaust gas is pulled from the manifold through a thin tube, thereby cooling the gas. A vacuum created in the engine pulls the gas through a computer-controlled EGR valve into a collection chamber where it further cools. In this chamber, entrained heavy particulate matter of unburned carbon particles are released, causing carbon deposits to accumulate over time within the EGR system. The deposits primarily affect the functioning of the EGR valve, which controls the volume and timing of the recirculation of the exhaust gas. If a sufficient amount of such deposits accumulate, the chamber and the valve will become inefficient and produce an overly rich fuel mixture to the engine. The engine control system will then attempt to correct for this over rich mixture, but will eventually fail. Thus, the carbon deposits reduce not only the efficiency of the EGRsystem, but also the functioning of the combustion engine as a whole.
The carbon deposit buildup in the EGR system has been recognized by those in the industry as a significant problem. Several manufacturers have distributed service bulletins providing maintenance individuals with methods of eliminating the deposits. The most common method involves drilling holes into the manifold to gain access to the manifold. Once access to the manifold is achieved, the maintenance individual places a foreign object into the manifold, such as a coat hanger, and then vigorously moves the hanger within the manifold. The movement of the foreign object within the manifold is intended to dislodge the deposits and allow them to circulate through the system. Not only is this an extremely time consuming and crude exercise, but it also poses a serious hazard to the engine.
First, this proposed maintenance does not eliminate the deposits, but merely causes them to become dislodged and moved to other portions of the engine. The deposit debris can accumulate on the valves or spark plugs of the engine, causing them to function improperly or, in some instances, to become inoperable. Second, the insertion of the foreign object into the manifold will often create metal slivers or shavings from the object. The existence of these metal slivers or shavings in the engine can be deleterious to the functioning of the engine. Whether the deposits and shavings accumulate on the valves, spark plugs or cylinder walls, the result is the possibility of serious damage to the vehicle engine.
The other common method prescribed by automobile manufacturers to clean the EGR system is to physically remove the manifold assembly and the submerge it in a cleaning liquid. This process is extremely time consuming and expensive. This method requires that the vehicle be out of service for an extended period of time, which is undesirable to the vehicle owner.
It is therefore an objective of the present invention to provide a method and apparatus for cleaning the EGR system of a vehicle that is effective, but simple and inexpensive to perform. More particularly, it is an object of the present invention to provide a method and apparatus for cleaning the EGR system of a vehicle employing a solvent that dissolves the carbon deposits within the system so that they may be eliminated without the risk of creating deposit debris.
Still more particularly, it is an object of the present invention to provide a method and apparatus for cleaning the EGR system of a vehicle that administers atomized solvent to the EGR system to break down and dissolve carbon deposits throughout the manifold.
It is another object of present invention to provide a method and apparatus for cleaning the EGR system of a vehicle that does not require the drilling of access holes into the engine.
It is also an object of present invention to provide a method and apparatus for cleaning the EGR system of a vehicle that does not require the dismantling and flushing of the EGR components.
It is yet another object of the present invention to provide a method and apparatus for cleaning the EGR system of a vehicle that employs adaptor plates conforming to the existing configurations of EGR valves on conventional combustion engines so that the method and apparatus can be used on any commercially produced vehicle.
It is an overall object of the present invention to provide a system for cleaning the EGR system of a vehicle that overcomes the deficiencies of other methods currently used in the art.
To accomplish these and other related objects, a method and apparatus for cleaning the EGR system of a vehicle is disclosed. The apparatus includes an induction device that is removably attachable to the manifold of an engine in the location of the EGR valve. The induction device includes a venturi cap defining a central cavity and having multiple circumferential bores for accessing ambient air. The apparatus further includes a solvent, having a composition of chemicals for dissolving the deposits within the EGR system, and a solvent administrator removably attachable to the induction device for providing a quantity of solvent to the EGR system. Finally, the present invention includes supplemental steps for ensuring the EGR system is completely cleaned and maintained for subsequent use.